Glasses and glass-ceramics with high specific young's modulus and their applications

US6376402B1 · kind B1 · utility

Assignee

• Schott Glas · DE

Inventors

• Wolfgang Pannhorst · Mainz, DE
• Ute Woelfel · Bingen, DE
• Silke Wolff · Hückeswagen, DE

Key dates

• Filing date: Apr 19, 2000
• Grant date: Apr 23, 2002
• Expiry date: Apr 19, 2020

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C03C10/0027
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The glass or glass-ceramic has the following composition (in % by weight based on oxide content): SiO2, 25 to 50; B2O3, >5 to 16; Al2O3, 10 to 17; P2O5, 0 to 8; Li2O,5 to 15; Na2O, 0 to 10; K2O, 0 to 10; MgO, 10 to 30; CaO, 0 to 10; SrO, 0 to 8; ZnO, 0 to 8; TiO2, 0.1 to 10; ZrO2, 0 to 8; and at least one refining agent, in an amount as needed according to its purpose. The sum total amount of divalent metal oxides (RO) present is less or equal to than 45% by weight based on oxide content and the sum total amount of alkali metal oxides (R2O) present is less than or equal to 30% by weight based on oxide content. The glass or glass-ceramic material generally has elasticity modulus values (E)>90&times;103 N/mm2 and <125&times;103 N/mm2, specific elasticity modulus values (E/&rgr;)>30&times;105 N cm/g and <45&times;105 N cm/g and thermal expansion coefficient values (&agr;20/300)>7.0&times;10&#8722;6/K and <11.0&times;10&#8722;6/K. The material is outstandingly suitable for making fixed disk substrates.